We are a I 0-member group at Brandeis focused on developing and describing state-of-the-art x-ray detectors for applications in structural biology and medical imaging. This involves the design and fabrication of hardware, electronics, and software for data-collection and data-processing. Design criteria include: (1) a large area, (2) fast readout, (3) large dynamic range and (4) high spatial resolution. A four-module detector is under construction for the NSLS, to be used at beamlines X25 and X12-C. Objectives: This system will be installed during the first grant year. This detector will be characterized and improvements will be sought to the engineering of the detector, the readout logic and electronics, and, in cooperation with the software development project (9.c. 1. 1), integration with beamline and data-collection software. After the 4-module detector project is finished, we expect to continue development of CCD-based detectors in two areas that we believe offer exciting possibilities: (1) detectors with considerably faster readout for time-resolved and Laue-diffraction investigations, and (2) detectors based on large-area CCDs.